<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>圆角</title>
  <style>
    .box1 {
      width: 200px;
      height: 100px;
      background-color: red;
      margin-bottom: 20px;
      /* 设置圆角 */
      border-top-left-radius: 50px;
      border-bottom-right-radius: 50px;
      border-top-right-radius: 20px;
      border-bottom-left-radius: 10px;
    }
  </style>
</head>

<body>
  <div class="box1"></div>
</body>

</html>